Note 11 - Provision for Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Provision For Income Taxes [Abstract]
Current Federal income taxes									$ 2,569	$ 2,375	$ 1,742
Current state income taxes									52	156	57
Deferred Federal income taxes (benefits)									(53)	207	363
Deferred state income taxes (benefits)									(6)	112	(105)
Other									0	0	(85)
Net provision prior to discrete tax adjustments									2,562	2,850	1,972
DTL writeoff due to change in tax methods									0	0	(415)
Net provision	$ 1,056	$ 914	$ 998	$ (406)	$ 623	$ 731	$ 679	$ 817	$ 2,562	$ 2,850	$ 1,557